Window balance

Question

I think the brand is Mastic. The balance is made out of steel, it is 16" long, 1/2" wide and has the number 1601 stamped on it, further down it says BSI

Jasmine · Accepted Answer

Thanks for posting! Your channel balance resembles the S770-16. To determine the stamp needed for your balance, you'll need to confirm the exact weight of the sash. I am unable to cross-reference the stamp from your balances so you'll need the window weight to determine the stamp needed to support your sashes.

Once you've confirmed the weight, you'll be able to confirm the stamp based on the weight ranges shown below the product description of the S770-16 channel balance.